Abstract
Perception and action are coupled such that actions within an environment change the perceptions of the objects within the environment (Gibson, 1979). Likewise changes to an individual's action capabilities (balance) affect his or her perceptions (Geuss & Stefanucci, 2010). The objective of the current study was to determine if previously observed age-related differences in actions (Hackney & Cinelli, 2010) were due to differences in perception. Our hypothesis was that age-related differences in balance stability lead to differences in perception that in turn produce differences in actions. Young (n = 10) and older adults (n = 6) performed 3 blocks of trials (static perceptions, dynamic perceptions, & action). The first two blocks were counter-balanced and required the participants to give a yes/no response as to whether they could pass through an aperture (0.9–1.8 times shoulder width) without rotating their shoulders. Both perceptual judgements were made 5 m from the aperture either standing or approaching the mark from 9 m away respectively. The action block required participants to walked down the 9 m path at a self-selected pace and pass through the aperture (1–1.8× SW) using a suitable method. Action results revealed that older adults begin to rotate shoulders at larger apertures than young adults (∼1.6 and ∼1.4× SW respectively, p < 0.05). Perception results revealed that static perceptions were not different between young and older adults, however, older adults had more conservative dynamic perceptions (p < 0.05). Therefore, it is possible that the decreased dynamic stability of older adult's leads to changes in dynamic perception causing more cautious actions.